Risk Factors for Major Amputation in Chronic Limb-Threatening Ischemia Patients Classified as Wound, Ischemia, and Foot Infection Stage 4 following Infrainguinal Revascularization

Abstract

To evaluate limb salvage outcomes and risk factors for major amputation in chronic limb-threatening ischemia (CLTI) patients classified as Stage 4 per the Wound, Ischemia, and foot Infection (WIfI) classification following infrainguinal revascularization. We retrospectively analyzed multicenter data of patients who had undergone infrainguinal revascularization for CLTI between 2015 and 2020. The endpoint was secondary major amputation defined as an above- or below-knee amputation following infrainguinal revascularization. We analyzed 243 patients with CLTI and 267 limbs. Bypass surgery was performed in 14 (25.5%) and 120 (56.6%) limbs from the secondary major amputation and limb salvage groups, respectively (P < .01). Endovascular therapy (EVT) was performed in 41 limbs (74.5%) in the secondary major amputation group and 92 limbs (43.4%) in the limb salvage group (P < .01). The average serum albumin levels were 3.0 ± 0.6 and 3.4 ± 0.5 g/dL in the secondary major amputation and limb salvage groups, respectively (P < .01). The percentage of congestive heart failure (CHF) was 36.4% and 14.2% in secondary major amputation and limb salvage groups, respectively (P < .01). The number of limbs with infra-malleolar (IM) P0, P1, and P2 were 4 (7.3%), 37 (67.3%), and 14 (25.5%), respectively, in the secondary major amputation group and 58 (27.4%), 140 (66.0%), and 14 (6.6%), respectively, in the limb salvage group (P < .01). Limb salvage rates at 1-year were 91.0% and 68.6% in the bypass and EVT groups, respectively (P < .01). Limb salvage rates at 1-year in patients with IM P0, P1, and P2 were 91.8%, 79.9%, and 53.1%, respectively (P < .01) Multivariate analysis revealed that serum albumin level [Hazard ratio (HR), 0.56; 95% confidence interval (CI), 0.36-0.89; P = .01], hypertension (HR, 0.39; 95% CI, 0.21-0.75; P < .01), CHF (HR, 2.10; 95% CI, 1.09-4.05; P = .03), wound grade (HR, 1.72; 95% CI, 1.03-2.88; P = .04), IM P (HR, 2.08; 95% CI, 1.27-3.42; P < .01), and EVT (HR, 3.31; 95% CI, 1.77-6.18; P < .01) as independent risk factors for secondary major amputation being required. Among CLTI patients with WIfI stage 4, the limb salvage rate was poor in those with IM P1-2 following infrainguinal EVT. Low serum albumin levels, CHF, high wound grade, IM P1-2, and EVT were independent risk factors for CLTI patients requiring major amputation.